Supreme Court of New Zealand

Structural Designer

Holmes Consulting Group

Client Name

Ministry of Justice, New Zealand Government

PROJECT DESCRIPTION

The Supreme Court of New Zealand was established in 2004 as the final court of appeal. The project combined a new Supreme Court building with the restoration of the existing Old High Court building, both with a design life of 100 years. The Old High Court Building, completed in 1881, was the first masonry building in Wellington.

The floors and roof are of timber construction. The structure was assessed using non-linear time history analysis. A base isolation solution was adopted as it enabled earthquake strengthening to be achieved with minimal intrusion into the heritage fabric, and virtually no visible impact. The building was cut off from its existing foundations and a new concrete ground floor diaphragm installed, designed to move up to 250mm at the isolation plane. The existing concrete bored piles support the completed structure, with new screw piles under previous additions that were on shallow foundations.

The new building is on reclamation fill with a high water table. Screw piles resist the uplift pressures on the basement slab. Above the ground floor transfer diaphragm, the building uses a column hinging limited ductility moment resisting concrete frame. The Supreme Courtroom creates a large void in the floor plates. Where this cuts through the moment frames the beams are supported by cranked steel columns. Key elements such as the spiral staircase and the external shading screen required sensitive engineering and detailing to work with the architectural intentions.

Judge's comment:

"The structural engineering provided an intelligent and sensitive response to the brief."